CA gets worse with time?

> The chromatic aberration was never that good with my 1st digicam: an
> Olympus C4040 from the start but I'm sure it got worse after a while. My
> current PowewrShot A710IS was virtually free from it when bought but is
> showing increasing levels of it.
> It's either my fertile imagination or physical wear in the cams?!

I have no idea if this could be a cause, but over time you can get a fair
amount of condensation and even mold on the inside surfaces of the lenses.
Could that possibly distort light in such a way as to increase CA? What
*would* the effect of mold be on an image (besides presumably making it a
bit softer)?

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
 >> Stay informed about: CA gets worse with time? 

"Zed" <Zed.RemoveThis@someplace.com> wrote in message
news:ZvydnY1Ccpqly9_bnZ2dnUVZ8qeknZ2d@pipex.net...
> The chromatic aberration was never that good with my 1st digicam: an
> Olympus C4040 from the start but I'm sure it got worse after a while. My
> current PowewrShot A710IS was virtually free from it when bought but is
> showing increasing levels of it.
> It's either my fertile imagination or physical wear in the cams?!
>
I think it is you. It is possible for a lens to become misaligned, but you'd
probably notice other artifacts along with CA.
John
 >> Stay informed about: CA gets worse with time? 

Mike Jacoubowsky wrote:
>> The chromatic aberration was never that good with my 1st digicam: an
>> Olympus C4040 from the start but I'm sure it got worse after a while. My
>> current PowewrShot A710IS was virtually free from it when bought but is
>> showing increasing levels of it.
>> It's either my fertile imagination or physical wear in the cams?!
>
> I have no idea if this could be a cause, but over time you can get a fair
> amount of condensation and even mold on the inside surfaces of the lenses.
> Could that possibly distort light in such a way as to increase CA? What
> *would* the effect of mold be on an image (besides presumably making it a
> bit softer)?
>
> --Mike-- Chain Reaction Bicycles
> www.ChainReactionBicycles.com
>
>
Mold would scatter light, and affect the resolution. It
should not introduce CA. Ca is caused by the differences in
the refractive index vs wavelength of each lens element.
This is controlled by the choice of materials of the
individual elements. It does not change with time.
 >> Stay informed about: CA gets worse with time? 

"Zed" <Zed.DeleteThis@someplace.com> wrote in message
news:ZvydnY1Ccpqly9_bnZ2dnUVZ8qeknZ2d@pipex.net...
> The chromatic aberration was never that good with my 1st digicam: an
> Olympus C4040 from the start but I'm sure it got worse after a while. My
> current PowewrShot A710IS was virtually free from it when bought but is
> showing increasing levels of it.
> It's either my fertile imagination or physical wear in the cams?!
Yes, I agree wholeheartedly. Ooops, you mean chromatic aberration gets
worse, not California...nevermind
nevermind
 >> Stay informed about: CA gets worse with time? 

>> I have no idea if this could be a cause, but over time you can get a fair
>> amount of condensation and even mold on the inside surfaces of the
>> lenses. Could that possibly distort light in such a way as to increase
>> CA? What *would* the effect of mold be on an image (besides presumably
>> making it a bit softer)?
>>
>> --Mike-- Chain Reaction Bicycles
>> www.ChainReactionBicycles.com
> Mold would scatter light, and affect the resolution. It should not
> introduce CA. Ca is caused by the differences in the refractive index vs
> wavelength of each lens element. This is controlled by the choice of
> materials of the individual elements. It does not change with time.

Thanks, that makes sense. It would be interesting to know more about the
effects of repeated condensation cycles (and possible mold growth) in
cameras over time, as in what's affected, and whether anything can be done
about it. I suspect my pocketable digicams develop issues over time, due to
carrying them in my rear jesey pocket while cycling, often on very hot days
when it would be subject to a fair amount of condensation from sweat, and at
other times, from dampness in the air.

I probably don't want to think about the damage I do to my poor cameras...
on the other hand, I've never had a failure in the field, and as I've taken
many, many thousands of photos with each, it's not as if they haven't gotten
a workout. But I've never tested them by shooting a test pattern when new
and then another one down the road.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
 >> Stay informed about: CA gets worse with time? 

Marvin <physchem.RemoveThis@cloud9.net> wrote:
> Mike Jacoubowsky wrote:
>>> The chromatic aberration was never that good with my 1st digicam: an
>>> Olympus C4040 from the start but I'm sure it got worse after a while. My
>>> current PowewrShot A710IS was virtually free from it when bought but is
>>> showing increasing levels of it.
>>> It's either my fertile imagination or physical wear in the cams?!
>>
>> I have no idea if this could be a cause, but over time you can get a fair
>> amount of condensation and even mold on the inside surfaces of the lenses.
>> Could that possibly distort light in such a way as to increase CA? What
>> *would* the effect of mold be on an image (besides presumably making it a
>> bit softer)?

> Mold would scatter light, and affect the resolution. It
> should not introduce CA. Ca is caused by the differences in
> the refractive index vs wavelength of each lens element.
> This is controlled by the choice of materials of the
> individual elements. It does not change with time.

THe only thing I can think of that would increase chromatic aberration
would be misalignment of the lens or a lens element due to a serious
knock. If that happened you'd very likely to get asymmetric CA, i.e.,
different at left nd right or top and bottom. With a properly aligned
lens it ought to be good in the middle and degrade symmetrically
towards the edges.

But note that most cameras are built to take pretty serious knocks,
e.g. the not uncommon nasty noise on a windy mountain summit of a
dropped DSLR hitting rock

--
Chris Malcolm cam.RemoveThis@infirmatics.ed.ac.uk DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]
 >> Stay informed about: CA gets worse with time? 

Thus spake John Smith:
> "Zed" <Zed.RemoveThis@someplace.com> wrote in message
> news:ZvydnY1Ccpqly9_bnZ2dnUVZ8qeknZ2d@pipex.net...
>> The chromatic aberration was never that good with my 1st digicam: an
>> Olympus C4040 from the start but I'm sure it got worse after a
>> while. My current PowewrShot A710IS was virtually free from it when
>> bought but is showing increasing levels of it.
>> It's either my fertile imagination or physical wear in the cams?!
>
>
> Probably the bloom is off the camera,and you're becoming more
> critical, looking for an excuse to upgrade.

LOL!

Looking for an excuse to upgrade? The Canon A710 is a very good P&S but the
excuse I have for *not* upgrading is simply that I don't have the money or
likely to have enough until next year. As for just getting more critical, I
knew very early on that CA was one of this model's weaknesses from reading
reviews

Looking through the photos taken on the Olympus, I'd say that CA has
worsened. I didn't notice at 1st, probably because I never thought it was
possible. I read a post (maybe on this very NG) that someone mentioned that
CA has deteriorated on their camera. I made a mental note & that's all. It
wasn't until I thought that it had got worse on mine that I thought about
how it could happen. Autofocus will compensate for mechanical wear to some
degree but I'm unwilling to dismiss that an increase in CA might be caused
by this. It may not be the case but it sounds plausible to me. The camera
has not sustained a knock & I've not heard that the sensors deteriorate with
age alone.
 >> Stay informed about: CA gets worse with time? 

"Zed" <Zed.RemoveThis@someplace.com> wrote in message
news:aOydnX5QY4D2y9XbnZ2dnUVZ8vmdnZ2d@pipex.net...
> Thus spake John Smith:
>> "Zed" <Zed.RemoveThis@someplace.com> wrote in message
>> news:ZvydnY1Ccpqly9_bnZ2dnUVZ8qeknZ2d@pipex.net...
>>> The chromatic aberration was never that good with my 1st digicam: an
>>> Olympus C4040 from the start but I'm sure it got worse after a
>>> while. My current PowewrShot A710IS was virtually free from it when
>>> bought but is showing increasing levels of it.
>>> It's either my fertile imagination or physical wear in the cams?!
>>
>>
>> Probably the bloom is off the camera,and you're becoming more
>> critical, looking for an excuse to upgrade.
>
> LOL!
>
> Looking for an excuse to upgrade? The Canon A710 is a very good P&S but
> the excuse I have for *not* upgrading is simply that I don't have the
> money or likely to have enough until next year. As for just getting more
> critical, I knew very early on that CA was one of this model's weaknesses
> from reading reviews
>
> Looking through the photos taken on the Olympus, I'd say that CA has
> worsened. I didn't notice at 1st, probably because I never thought it was
> possible. I read a post (maybe on this very NG) that someone mentioned
> that CA has deteriorated on their camera. I made a mental note & that's
> all. It wasn't until I thought that it had got worse on mine that I
> thought about how it could happen. Autofocus will compensate for
> mechanical wear to some degree but I'm unwilling to dismiss that an
> increase in CA might be caused by this. It may not be the case but it
> sounds plausible to me. The camera has not sustained a knock & I've not
> heard that the sensors deteriorate with age alone.

Have you compared one of your earlier photos with a recent one of a similar
subject, taken under similar conditions? That would seem to give a better
answer than any guessing about your camera that any of us can do.
--

Mike Russell
www.curvemeister.com/forum/
 >> Stay informed about: CA gets worse with time? 

Thus spake Mike Russell:
>>>> The chromatic aberration was never that good with my 1st digicam:
>>>> an Olympus C4040 from the start but I'm sure it got worse after a
>>>> while. My current PowewrShot A710IS was virtually free from it when
>>>> bought but is showing increasing levels of it.
>>>> It's either my fertile imagination or physical wear in the cams?!
>
> Have you compared one of your earlier photos with a recent one of a
> similar subject, taken under similar conditions? That would seem to
> give a better answer than any guessing about your camera that any of
> us can do. --
>
> Mike Russell
> www.curvemeister.com/forum/

The problem here is that CA wasn't very consistent between shots over a
short period of time hence my asking if others had noticed any degradation.
As the consensus is no, I'll not worry too much about it - especially as my
C4040 isn't used anymore & it's hardly bad on my Canon.

--
Basically, I hate people who preface nearly every sentence with the word
'basically'!
 >> Stay informed about: CA gets worse with time? 

I have noticed slightly variable CA on my Nikon 8800. Also, the
sharpness of the images can change a bit from shot to shot. By using a
variety of techniques, I concluded that the likely explanation was the
image stabilization. That is achieved by moving a lens element a bit,
which means it can move a bit off-axis where the alignment is degraded.
If I turn off the IS, all imgages are equally sharp and have the same
low CA, but if I turn it on, I can see variable CA and sharpness of a
kind I could interpret as a off-center element. If I simply turn off the
IS and turn it on, the next image is likely to be better than the last
one before. This is all a bit subtle and of no practical consequence,
and maybe I'm fooling myself about the interpretation, but I was very
careful and took lots of images to investigate this when I got some
slightly puzzeling results comparing my 8800 to my new Canon SD700IS.

Joe



Zed wrote:
> Thus spake Mike Russell:
>
>>>>>The chromatic aberration was never that good with my 1st digicam:
>>>>>an Olympus C4040 from the start but I'm sure it got worse after a
>>>>>while. My current PowewrShot A710IS was virtually free from it when
>>>>>bought but is showing increasing levels of it.
>>>>>It's either my fertile imagination or physical wear in the cams?!
>>
>>Have you compared one of your earlier photos with a recent one of a
>>similar subject, taken under similar conditions? That would seem to
>>give a better answer than any guessing about your camera that any of
>>us can do. --
>>
>>Mike Russell
>>www.curvemeister.com/forum/
>
>
> The problem here is that CA wasn't very consistent between shots over a
> short period of time hence my asking if others had noticed any degradation.
> As the consensus is no, I'll not worry too much about it - especially as my
> C4040 isn't used anymore & it's hardly bad on my Canon.
>
 >> Stay informed about: CA gets worse with time?